1. Technical Field
The invention relates to a door lock system installed on board an aircraft and operative to controllably and selectively open and close multiple passage barriers. In particular, the invention relates to a door lock system providing controllable access to restricted areas on board an aircraft.
2. Background of Related Art
As part of administrative efforts to increase aircraft security, the U.S. Department of Transportation""s Federal Aviation Administration (FAA) recently announced plans to distribute $100 million that Congress appropriated for security enhancements to aircraft flight decks and cabins. Funds will soon be distributed to air carriers to install video and other technology for use in the cabin and to fortify flight deck doors. Primarily, the latter involves improving locks and other barriers already installed, as well as permanent design changes that must be in place by April 2003. xe2x80x9cPreventing unauthorized access to the cockpit is one of our highest priorities, but it""s also essential that the flight crew and cabin crew have technology to help them work as a team in a threat situation,xe2x80x9d said the FAA. The President announced on Sep. 28, 2001 that he was requesting funding from Congress to help the U.S. airline and cargo industry finance cockpit door modifications and alerting systems.
Current doors are not adequately designed to minimize or mitigate the negative impacts from breaches caused by blunt force, ballistics, fragmentation, or other explosive. Typically, strengthening of the flight deck door can be divided into the following areas: improved locking, hinge, door handle, and doorframe integrity.
One of the known designs relates to a so-called xe2x80x9cplugxe2x80x9d type door system with a door panel supported for sequential movement between a door closed position, wherein the door panel is prevented from lateral opening movements, and a door open position with the door panel pivoted and moved to a position conforming to an outside contour of the aircraft body adjacent the door frame.
In the door system of this type known from U.S. Pat. No. 5,163,639, separate electric motors are provided for raising and lowering, pivoting inward and outward, and locking of the door panel in the completely closed position. This door system has a limited functional reliability, because if only one of the electric motors or the program control fails, the entire door system will malfunction, potentially in the open position.
A door lock system for selectively operating adjacent doors to secure or control access into a space therebetween is well known and widely used to monitor access to the banks, stores and buildings. However, such systems have not been developed for aircraft building industry.
It is, therefore, desirable to provide restricted areas on board aircraft and particularly, its cockpit area, with a door lock system minimizing the possibility of unauthorized entry into the pilot""s cabin.
It is an object of the invention to provide a door lock system minimizing the risk of unauthorized entry into restricted areas on board an aircraft.
Another object of the invention is to provide the door lock system including a system for monitoring the restricted area and for alarming authorized personnel in case of emergency.
Yet a further object of the invention is to provide the slideable barriers of the inventive lock system with an adjustable structure operative to conform to the shape of the fuselage of an aircraft.
Consonant with the above listed objects, the present invention includes a door lock assembly for selectively operating the opening and closing of at least two inner and outer passage barriers or doors to control entry into the space defined between these barriers. Advantageously, the inventive door lock system operates to prevent an unauthorized entry into the cockpit area, which is usually a space enclosed in the forward fuselage of an airplane and designed as a pilot""s cabin. In addition, part of this space can be used as a utility area located between the pilot""s cabin and the first class section. Often, the utility area is configured as a front galley module. Application of the inventive door lock system, however, is not limited to the cockpit area and can be successfully utilized for controlling access to any restricted area on board.
In accordance with one aspect of the invention, the door lock system controls access into the cockpit area by controllably allowing a requestor to pass through the outer barrier, which can be any door or partition blocking or impeding the passage, while the inner door leading to the pilot""s cabin is closed.
The inventive system provides security in at least three ways. It makes it difficult to forcibly gain entry by knocking down a single door, it allows time to evaluate the person in the mantrap before releasing him or her through either of the doors, and it allows entry of only one person at a time.
In accordance with another aspect of this invention, the door lock system does not allow the person to pass through the inner pilot cabin door until the outer barrier is closed and locked. Conversely, according to a further aspect of the invention, a voluntary exit from the controlled space is blocked unless the inner pilot cabin door is locked.
Still another aspect of the invention includes a manual mode of operation of the inventive system in which the automatic sequential opening of the inner and outer doors in case of emergency is disabled.
In accordance with a further aspect of the invention, the door lock system may include additional sensors capable of positively identifying authorized personnel. The entry may be allowed by using a variety of identifying means including, for example, biometric sensors capable of identifying voices, fingerprints and the like of authorized personnel. To further enhance the door lock system, a camera surveying the controlled area as well as a monitor connected to the camera and installed in the pilot""s cabin can be automatically turned on in response to the unlocking and opening of the outer door. If the camera is constantly on, unobtrusive signaling means, such as weak sound and/or light signals, can attract attention of crewmember to the monitor in response to the operation of the outer door. In case of emergency, the door lock system can be provided with a controller setting a lock-in hijacking code, which can be transmitted to on-ground facilities in response to a signal generated by the crewmembers or automatically if certain safety conditions are not met. A satellite link establishing, for example, visual and sound contact between the aircraft and the monitoring on-ground facility, such as air traffic control (ATC) can be easily employed to provide such communication.
In a further aspect of the invention, the door lock system includes the sliding barriers. Because of the annular shape of the fuselage, at least the inner door leading to the pilot cabin is provided with a retractable corner to conform to the shape of the fuselage in an open position of the door.